Thermoplastic processing of grade 2 titanium: Finite element method simulations and experimental validation with the Anand model

This work examined thermoplastic processing (TMP) of commercially pure Grade 2 titanium using finite element simulations with the Anand viscoplastic constitutive model and a broad experimental validation matrix (400-800 °C; 0.01-10 s⁻¹, including an intermediate 5 s⁻¹ case).The goal was to assess whether this model, originally developed for solder alloys, can capture the deformation behaviour of titanium at elevated temperatures, relevant to biomedical applications.Uniaxial compression tests were performed at 400-800 °C and strain rates of 0.01-10 s⁻¹, and the resulting stress-strain curves were compared with the FEM simulations in Ansys Workbench.Parameter calibration was based on experimental data, with focus on 500-600 °C and 0.1-1 s⁻¹ -conditions previously shown to promote grain refinement and mechanical strengthening.The Anand model reproduced stress evolution well in the initial deformation phase, particularly at lower strain rates.Stress distributions in the FEM simulations captured the expected axial stress gradients (centre < side < edge), while stresses were typically 30-40 MPa higher than measured.The model also reproduced the elastic-plastic transition, with smoother behaviour observed at higher temperatures.However, the model does not account for dynamic recrystallisation (DRX) or related softening mechanisms, which leads to overestimation of stresses in the later stages of deformation.Experimental samples also displayed anisotropic deformation, likely due to initial material texture, which was not represented in the model.Despite these limitations, the Anand formulation demonstrates potential for predicting TMP of pure titanium, reducing reliance on trial-and-error testing and supporting process optimisation for biomedical applications.